Sporulation in the prokaryotic Bacillus subtilis can be initiated by the partial deprivation of amino acids, which causes a "stringent response". Certain antibiotics prevented this induction with almost no inhibition of growth. Their effect was counteracted by decoyinine which specifically inhibits the synthesis of guanosine monophosphate (GMP). The stringent response also inhibited the uptake of guanine and uracil, but only the latter was also inhibited by addition of decoyinine alone. To understand the mechanisms controlling the synthesis of a typical developmental protein, the gene for glucose dehydrogenase of Bacillus subtilis was cloned in several plasmids. In the non-differentiating E. coli, these plasmids caused production of active glucose dehydrogenase during vegetative growth. However, a low copy plasmid shuttle vector produced essentially no glucose dehydrogenase activity in B. subtilis, and a high copy plasmid produced a low amount of enzyme; this suggests the titration of a repressor. In vitro, the gene could be transcribed into RNA, but only by a minor component of RNA-polymerase of B. subtilis which may play a special development role. The turnover of B. subtilis cell wall was measured under many different growth conditions and found to be almost proportional to the growth rate. In various lyt mutants, no correlation between the rate of turnover and that of autolysis was observed.